feat(parsers.avro): Support multiple modes for union handling

plugins/parsers/avro/README.md

@@ -107,6 +107,12 @@ the error will be rised and the message will not be parsed.
   ## If this were set to "_", then it would be a_0="a", a_1="b".
   # avro_field_separator = "_"
 
+  ## Define handling of union types. Possible values are:
+  ##   flatten  -- add type suffix to field name (default)
+  ##   nullable -- do not modify field name but discard "null" field values
+  ##   any      -- do not modify field name and set field value to the received type
+  # avro_union_mode = "flatten"
+
   ## Default values for given tags: optional
   # tags = { "application": "hermes", "region": "central" }
 

plugins/parsers/avro/parser.go

@@ -36,10 +36,10 @@ type Parser struct {
 	Timestamp        string            `toml:"avro_timestamp"`
 	TimestampFormat  string            `toml:"avro_timestamp_format"`
 	FieldSeparator   string            `toml:"avro_field_separator"`
+	UnionMode        string            `toml:"avro_union_mode"`
 	DefaultTags      map[string]string `toml:"tags"`
-
-	Log         telegraf.Logger `toml:"-"`
-	registryObj *schemaRegistry
+	Log              telegraf.Logger   `toml:"-"`
+	registryObj      *schemaRegistry
 }
 
 func (p *Parser) Init() error {
@@ -51,6 +51,14 @@ func (p *Parser) Init() error {
 	default:
 		return fmt.Errorf("unknown 'avro_format' %q", p.Format)
 	}
+	switch p.UnionMode {
+	case "":
+		p.UnionMode = "flatten"
+	case "flatten", "nullable", "any":
+		// Do nothing as those are valid settings
+	default:
+		return fmt.Errorf("unknown avro_union_mode %q", p.Format)
+	}
 
 	if (p.Schema == "" && p.SchemaRegistry == "") || (p.Schema != "" && p.SchemaRegistry != "") {
 		return errors.New("exactly one of 'schema_registry' or 'schema' must be specified")
@@ -153,6 +161,25 @@ func (p *Parser) SetDefaultTags(tags map[string]string) {
 	p.DefaultTags = tags
 }
 
+func (p *Parser) flattenField(fldName string, fldVal map[string]interface{}) map[string]interface{} {
+	// Helper function for the "nullable" and "any" p.UnionModes
+	// fldVal is a one-item map of string-to-something
+	ret := make(map[string]interface{})
+	if p.UnionMode == "nullable" {
+		_, ok := fldVal["null"]
+		if ok {
+			return ret // Return the empty map
+		}
+	}
+	// Otherwise, we just return the value in the fieldname.
+	// See README.md for an important warning about "any" and "nullable".
+	for _, v := range fldVal {
+		ret[fldName] = v
+		break // Not really needed, since it's a one-item map
+	}
+	return ret
+}
+
 func (p *Parser) createMetric(data map[string]interface{}, schema string) (telegraf.Metric, error) {
 	// Tags differ from fields, in that tags are inherently strings.
 	// fields can be of any type.
@@ -196,15 +223,36 @@ func (p *Parser) createMetric(data map[string]interface{}, schema string) (teleg
 	for _, fld := range fieldList {
 		candidate := make(map[string]interface{})
 		candidate[fld] = data[fld] // 1-item map
-		flat, err := flatten.Flatten(candidate, "", sep)
+		var flat map[string]interface{}
+		var err error
+		// Exactly how we flatten is decided by p.UnionMode
+		if p.UnionMode == "flatten" {
+			flat, err = flatten.Flatten(candidate, "", sep)
+			if err != nil {
+				return nil, fmt.Errorf("flatten candidate %q failed: %w", candidate, err)
+			}
+		} else {
+			// "nullable" or "any"
+			typedVal, ok := candidate[fld].(map[string]interface{})
+			if !ok {
+				// the "key" is not a string, so ...
+				// most likely an array?  Do the default thing
+				// and flatten the candidate.
+				flat, err = flatten.Flatten(candidate, "", sep)
+				if err != nil {
+					return nil, fmt.Errorf("flatten candidate %q failed: %w", candidate, err)
+				}
+			} else {
+				flat = p.flattenField(fld, typedVal)
+			}
+		}
 		if err != nil {
 			return nil, fmt.Errorf("flatten field %q failed: %w", fld, err)
 		}
 		for k, v := range flat {
 			fields[k] = v
 		}
 	}
-
 	var schemaObj map[string]interface{}
 	if err := json.Unmarshal([]byte(schema), &schemaObj); err != nil {
 		return nil, fmt.Errorf("unmarshaling schema failed: %w", err)

plugins/parsers/avro/testdata/json-array/expected.out

@@ -0,0 +1 @@
+array,name=pi data_0=3,data_1=3.0999999046325684,data_2=3.140000104904175,data_3=3.1410000324249268 1682509200092000

plugins/parsers/avro/testdata/json-array/message.json

@@ -0,0 +1,5 @@
+{
+    "statistics_collection_time": 1682509200092,  
+    "data": [ 3, 3.1, 3.14, 3.141 ],
+    "name": "pi"
+}

plugins/parsers/avro/testdata/json-array/telegraf.conf

@@ -0,0 +1,24 @@
+[[ inputs.file ]]
+  files = ["./testdata/json-array/message.json"]
+  data_format = "avro"
+
+  avro_format = "json"
+  avro_measurement = "array"
+  avro_tags = ["name"]
+  avro_timestamp = "statistics_collection_time"
+  avro_timestamp_format = "unix_ms"
+  avro_fields = ["data"]
+  avro_field_separator = "_"
+  avro_schema = '''
+        {
+                "namespace": "constants",
+                "name": "classical",
+                "type": "record",
+                "version": "1",
+                "fields": [
+                        {"name": "name", "type": "string"},
+			{"name": "data", "type": "array", "items": "float"},
+			{"name": "statistics_collection_time", "type": "long"}
+                ]
+        }
+  '''

plugins/parsers/avro/testdata/json-format/expected.out

@@ -1 +1 @@
-Switch,switch_wwn=10:00:50:EB:1A:0B:84:3A statistics_collection_time=1682509200092i,up_time=1166984904i,cpu_utilization=14.0,memory_utilization=20.0 1682509200092000
+Switch,switch_wwn=10:00:50:EB:1A:0B:84:3A up_time=1166984904i,cpu_utilization=14.0,memory_utilization=20.0 1682509200092000

plugins/parsers/avro/testdata/json-format/telegraf.conf

@@ -5,7 +5,7 @@
   avro_format = "json"
   avro_measurement = "Switch"
   avro_tags = ["switch_wwn"]
-  avro_fields = ["up_time", "cpu_utilization", "memory_utilization", "statistics_collection_time"]
+  avro_fields = ["up_time", "cpu_utilization", "memory_utilization"]
   avro_timestamp = "statistics_collection_time"
   avro_timestamp_format = "unix_ms"
   avro_schema = '''

plugins/parsers/avro/testdata/union-any/expected.out

@@ -0,0 +1 @@
+Switch,switch_wwn=10:00:50:EB:1A:0B:84:3A statistics_collection_time=1682509200092i,up_time=1166984904i,cpu_utilization=11i,memory_utilization=20.0 1682509200092000

plugins/parsers/avro/testdata/union-any/message.json

@@ -0,0 +1,11 @@
+{
+    "switch_wwn": "10:00:50:EB:1A:0B:84:3A",
+    "statistics_collection_time": 1682509200092,
+    "up_time": 1166984904,
+    "cpu_utilization": {
+      "int": 11
+    },
+    "memory_utilization": {
+      "float": 20.0
+    }
+}

plugins/parsers/avro/testdata/union-any/telegraf.conf

@@ -0,0 +1,26 @@
+[[ inputs.file ]]
+  files = ["./testdata/union-any/message.json"]
+  data_format = "avro"
+
+  avro_format = "json"
+  avro_measurement = "Switch"
+  avro_tags = ["switch_wwn"]
+  avro_fields = ["up_time", "cpu_utilization", "memory_utilization", "statistics_collection_time"]
+  avro_timestamp = "statistics_collection_time"
+  avro_timestamp_format = "unix_ms"
+  avro_union_mode = "any"
+  avro_schema = '''
+        {
+                "namespace": "com.brocade.streaming",
+                "name": "fibrechannel_switch_statistics",
+                "type": "record",
+                "version": "1",
+                "fields": [
+                        {"name": "switch_wwn", "type": "string", "doc": "WWN of the Physical Switch."},
+                        {"name": "statistics_collection_time", "type": "long", "doc": "Epoch time when statistics is collected."},
+                        {"name": "up_time", "type": "long", "doc": "Switch Up Time (in hundredths of a second)"},
+                        {"name": "cpu_utilization", "type": ["null", "float", "int"], "default": null, "doc": "CPU Utilization in %"},
+                        {"name": "memory_utilization", "type": ["null", "float"], "doc": "Memory Utilization in %"}
+                ]
+        }
+  '''

plugins/parsers/avro/testdata/union-array/expected.out

@@ -0,0 +1 @@
+array,name=pi data_0=3,data_1=3.0999999046325684,data_2=3.140000104904175,data_3=3.1410000324249268 1682509200092000

plugins/parsers/avro/testdata/union-array/message.json

@@ -0,0 +1,5 @@
+{
+    "statistics_collection_time": 1682509200092,  
+    "data": [ 3, 3.1, 3.14, 3.141 ],
+    "name": "pi"
+}

plugins/parsers/avro/testdata/union-array/telegraf.conf

@@ -0,0 +1,25 @@
+[[ inputs.file ]]
+  files = ["./testdata/json-array/message.json"]
+  data_format = "avro"
+
+  avro_format = "json"
+  avro_measurement = "array"
+  avro_tags = ["name"]
+  avro_timestamp = "statistics_collection_time"
+  avro_timestamp_format = "unix_ms"
+  avro_fields = ["data"]
+  avro_union_mode = "any"
+  avro_field_separator = "_"
+  avro_schema = '''
+        {
+                "namespace": "constants",
+                "name": "classical",
+                "type": "record",
+                "version": "1",
+                "fields": [
+                        {"name": "name", "type": "string"},
+			{"name": "data", "type": "array", "items": "float"},
+			{"name": "statistics_collection_time", "type": "long"}
+                ]
+        }
+  '''

plugins/parsers/avro/testdata/union-nullable/expected.out

@@ -0,0 +1 @@
+Switch,switch_wwn=10:00:50:EB:1A:0B:84:3A statistics_collection_time=1682509200092i,up_time=1166984904i,memory_utilization=20.0 1682509200092000

plugins/parsers/avro/testdata/union-nullable/message.json

@@ -0,0 +1,11 @@
+{
+    "switch_wwn": "10:00:50:EB:1A:0B:84:3A",
+    "statistics_collection_time": 1682509200092,
+    "up_time": 1166984904,
+    "cpu_utilization": {
+      "null": null
+    },
+    "memory_utilization": {
+      "float": 20.0
+    }
+}

plugins/parsers/avro/testdata/union-nullable/telegraf.conf

@@ -0,0 +1,26 @@
+[[ inputs.file ]]
+  files = ["./testdata/union-nullable/message.json"]
+  data_format = "avro"
+
+  avro_format = "json"
+  avro_measurement = "Switch"
+  avro_tags = ["switch_wwn"]
+  avro_fields = ["up_time", "cpu_utilization", "memory_utilization", "statistics_collection_time"]
+  avro_timestamp = "statistics_collection_time"
+  avro_timestamp_format = "unix_ms"
+  avro_union_mode = "nullable"
+  avro_schema = '''
+        {
+                "namespace": "com.brocade.streaming",
+                "name": "fibrechannel_switch_statistics",
+                "type": "record",
+                "version": "1",
+                "fields": [
+                        {"name": "switch_wwn", "type": "string", "doc": "WWN of the Physical Switch."},
+                        {"name": "statistics_collection_time", "type": "long", "doc": "Epoch time when statistics is collected."},
+                        {"name": "up_time", "type": "long", "doc": "Switch Up Time (in hundredths of a second)"},
+                        {"name": "cpu_utilization", "type": ["null","float"], "default": null, "doc": "CPU Utilization in %"},
+                        {"name": "memory_utilization", "type": ["null", "float"], "default": null, "doc": "Memory Utilization in %"}
+                ]
+        }
+  '''

plugins/parsers/avro/testdata/union/expected.out

@@ -0,0 +1 @@
+Switch,switch_wwn=10:00:50:EB:1A:0B:84:3A statistics_collection_time=1682509200092i,up_time=1166984904i,memory_utilization_float=20.0 1682509200092000

plugins/parsers/avro/testdata/union/message.json

@@ -0,0 +1,11 @@
+{
+    "switch_wwn": "10:00:50:EB:1A:0B:84:3A",
+    "statistics_collection_time": 1682509200092,
+    "up_time": 1166984904,
+    "cpu_utilization": {
+      "null": null
+    },
+    "memory_utilization": {
+      "float": 20.0
+    }
+}

plugins/parsers/avro/testdata/union/telegraf.conf

@@ -0,0 +1,26 @@
+[[ inputs.file ]]
+  files = ["./testdata/union/message.json"]
+  data_format = "avro"
+
+  avro_format = "json"
+  avro_measurement = "Switch"
+  avro_tags = ["switch_wwn"]
+  avro_fields = ["up_time", "cpu_utilization", "memory_utilization", "statistics_collection_time"]
+  avro_timestamp = "statistics_collection_time"
+  avro_timestamp_format = "unix_ms"
+  avro_field_separator = "_"
+  avro_schema = '''
+        {
+                "namespace": "com.brocade.streaming",
+                "name": "fibrechannel_switch_statistics",
+                "type": "record",
+                "version": "1",
+                "fields": [
+                        {"name": "switch_wwn", "type": "string", "doc": "WWN of the Physical Switch."},
+                        {"name": "statistics_collection_time", "type": "long", "doc": "Epoch time when statistics is collected."},
+                        {"name": "up_time", "type": "long", "doc": "Switch Up Time (in hundredths of a second)"},
+                        {"name": "cpu_utilization", "type": ["null", "float"], "default": null, "doc": "CPU Utilization in %"},
+                        {"name": "memory_utilization", "type": ["null", "float"], "default": null, "doc": "Memory Utilization in %"}
+                ]
+        }
+  '''